/*
 * rbtree.c
 *
 *  Created on: 2014年9月28日
 *      Author: copy from linux kernel
 */

#include <cm/struct/rbtree.h>

/*
 * @brief	将rbtree基于某个节点 左旋, 节点的右孩子必须不为NULL (右孩子为NULL还进行左旋？？！)
 */
static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
{
	struct rb_node *right = node->rb_right;
	struct rb_node *parent = rb_parent(node);

	if ((node->rb_right = right->rb_left))
		rb_set_parent(right->rb_left, node);/* step1: 将旋转点的右孩子的左孩子设为旋转点的右孩子 */

	right->rb_left = node;
	rb_set_parent(right, parent); /* step2: 将旋转点设为它自己右孩子的左孩子*/

	if (parent) { /*step3: 用旋转点的右孩子取代旋转点的位置 */
		if (node == parent->rb_left)
			parent->rb_left = right;
		else
			parent->rb_right = right;
	} else {
		root->rb_node = right;
	}
	rb_set_parent(node, right);
}

void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
{
	struct rb_node *left = node->rb_left;
	struct rb_node *parent = rb_parent(node);

	if ((node->rb_left = left->rb_right))
		rb_set_parent(left->rb_right, node);

	left->rb_right = node;
	rb_set_parent(left, parent);

	if (parent) {
		if (node == parent->rb_left)
			parent->rb_left = left;
		else
			parent->rb_right = left;
	} else {
		root->rb_node = left;
	}
	rb_set_parent(node, left);
}

/*
 * @brief	当某节点插入rbtree以后，对齐进行平衡(通过颜色)
 * 		注意：此时node已经是树中的一个节点, 且一定是叶子节点,且是红色
 */
void rb_insert_color(struct rb_node *node, struct rb_root *root)
{
	struct rb_node *parent, *gparent;

	/* 新节点是红色，若父节点是黑色则不违背红黑树的性质，不用调整，
	 若父节点是红色则违背不能有两个连续红色节点的性质 */
	while ((parent = rb_parent(node)) && rb_is_red(parent)) {
		gparent = rb_parent(parent);/* 父节点既然是红色，则其一定有祖父节点，因为根是黑色 */
		if (parent == gparent->rb_left) {
			{
				register struct rb_node *uncle =
						gparent->rb_right;
				if (uncle && rb_is_red(uncle)) {
					rb_set_black(uncle);
					rb_set_black(parent);
					rb_set_red(gparent);
					node = gparent;
					continue;
				}
			}
			if (parent->rb_right == node) {/* 此时： node没有uncle或者uncle是黑色，而父节点是红色 */
				register struct rb_node *tmp;
				__rb_rotate_left(parent, root);
				tmp = parent;
				parent = node;
				node = tmp;
			}
			rb_set_black(parent);
			rb_set_red(gparent);
			__rb_rotate_right(gparent, root);
		} else {
			{
				register struct rb_node *uncle =
						gparent->rb_left;
				if (uncle && rb_is_red(uncle)) {
					rb_set_black(uncle);
					rb_set_black(parent);
					rb_set_red(gparent);
					node = gparent;
					continue;
				}
			}
			if (parent->rb_left == node) {
				register struct rb_node *tmp;
				__rb_rotate_right(parent, root);
				tmp = parent;
				parent = node;
				node = tmp;
			}
			rb_set_black(parent);
			rb_set_red(gparent);
			__rb_rotate_left(gparent, root);
		}

	}
	rb_set_black(root->rb_node);
}

static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
		struct rb_root *root)
{
	struct rb_node *other;

	while ((!node || rb_is_black(node)) && node != root->rb_node) {
		if (parent->rb_left == node) {
			other = parent->rb_right;
			if (rb_is_red(other)) {
				rb_set_black(other);
				rb_set_red(parent);
				__rb_rotate_left(parent, root);
				other = parent->rb_right;
			}
			if ((!other->rb_left || rb_is_black(other->rb_left))
					&& (!other->rb_right
							|| rb_is_black(
									other->rb_right))) {
				rb_set_red(other);
				node = parent;
				parent = rb_parent(node);
			} else {
				if (!other->rb_right
						|| rb_is_black(other->rb_right)) {
					rb_set_black(other->rb_left);
					rb_set_red(other);
					__rb_rotate_right(other, root);
					other = parent->rb_right;
				}
				rb_set_color(other, rb_color(parent));
				rb_set_black(parent);
				rb_set_black(other->rb_right);
				__rb_rotate_left(parent, root);
				node = root->rb_node;
				break;
			}
		} else {
			other = parent->rb_left;
			if (rb_is_red(other)) {
				rb_set_black(other);
				rb_set_red(parent);
				__rb_rotate_right(parent, root);
				other = parent->rb_left;
			}
			if ((!other->rb_left || rb_is_black(other->rb_left))
					&& (!other->rb_right
							|| rb_is_black(
									other->rb_right))) {
				rb_set_red(other);
				node = parent;
				parent = rb_parent(node);
			} else {
				if (!other->rb_left
						|| rb_is_black(other->rb_left)) {
					rb_set_black(other->rb_right);
					rb_set_red(other);
					__rb_rotate_left(other, root);
					other = parent->rb_left;
				}
				rb_set_color(other, rb_color(parent));
				rb_set_black(parent);
				rb_set_black(other->rb_left);
				__rb_rotate_right(parent, root);
				node = root->rb_node;
				break;
			}
		}
	}
	if (node)
		rb_set_black(node);
}

void rb_erase(struct rb_node *node, struct rb_root *root)
{
	struct rb_node *child, *parent;
	int color;

	if (!node->rb_left)
		child = node->rb_right;
	else if (!node->rb_right)
		child = node->rb_left;
	else {
		struct rb_node *old = node, *left;

		node = node->rb_right;
		while ((left = node->rb_left) != NULL)
			node = left;

		if (rb_parent(old)) {
			if (rb_parent(old)->rb_left == old)
				rb_parent(old)->rb_left = node;
			else
				rb_parent(old)->rb_right = node;
		} else
			root->rb_node = node;

		child = node->rb_right;
		parent = rb_parent(node);
		color = rb_color(node);

		if (parent == old) {
			parent = node;
		} else {
			if (child)
				rb_set_parent(child, parent);
			parent->rb_left = child;

			node->rb_right = old->rb_right;
			rb_set_parent(old->rb_right, node);
		}

		node->rb_parent_color = old->rb_parent_color;
		node->rb_left = old->rb_left;
		rb_set_parent(old->rb_left, node);

		goto color;
	}

	parent = rb_parent(node);
	color = rb_color(node);

	if (child)
		rb_set_parent(child, parent);
	if (parent) {
		if (parent->rb_left == node)
			parent->rb_left = child;
		else
			parent->rb_right = child;
	} else
		root->rb_node = child;

	color: if (color == RB_BLACK)
		__rb_erase_color(child, parent, root);
}

static void rb_augment_path(struct rb_node *node, rb_augment_f func, void *data)
{
	struct rb_node *parent;

	up: func(node, data);
	parent = rb_parent(node);
	if (!parent)
		return;

	if (node == parent->rb_left && parent->rb_right)
		func(parent->rb_right, data);
	else if (parent->rb_left)
		func(parent->rb_left, data);

	node = parent;
	goto up;
}

/*
 * after inserting @node into the tree, update the tree to account for
 * both the new entry and any damage done by rebalance
 */
void rb_augment_insert(struct rb_node *node, rb_augment_f func, void *data)
{
	if (node->rb_left)
		node = node->rb_left;
	else if (node->rb_right)
		node = node->rb_right;

	rb_augment_path(node, func, data);
}

/*
 * before removing the node, find the deepest node on the rebalance path
 * that will still be there after @node gets removed
 */
struct rb_node *rb_augment_erase_begin(struct rb_node *node)
{
	struct rb_node *deepest;

	if (!node->rb_right && !node->rb_left)
		deepest = rb_parent(node);
	else if (!node->rb_right)
		deepest = node->rb_left;
	else if (!node->rb_left)
		deepest = node->rb_right;
	else {
		deepest = rb_next(node);
		if (deepest->rb_right)
			deepest = deepest->rb_right;
		else if (rb_parent(deepest) != node)
			deepest = rb_parent(deepest);
	}

	return deepest;
}

/*
 * after removal, update the tree to account for the removed entry
 * and any rebalance damage.
 */
void rb_augment_erase_end(struct rb_node *node, rb_augment_f func, void *data)
{
	if (node)
		rb_augment_path(node, func, data);
}

/*
 * This function returns the first node (in sort order) of the tree.
 */
struct rb_node *rb_first(const struct rb_root *root)
{
	struct rb_node *n;

	n = root->rb_node;
	if (!n)
		return NULL;
	while (n->rb_left)
		n = n->rb_left;
	return n;
}

struct rb_node *rb_last(const struct rb_root *root)
{
	struct rb_node *n;

	n = root->rb_node;
	if (!n)
		return NULL;
	while (n->rb_right)
		n = n->rb_right;
	return n;
}

struct rb_node *rb_next(const struct rb_node *node)
{
	struct rb_node *parent;

	if (rb_parent(node) == node)
		return NULL;

	/* If we have a right-hand child, go down and then left as far
	 as we can. */
	if (node->rb_right) {
		node = node->rb_right;
		while (node->rb_left)
			node = node->rb_left;
		return (struct rb_node *) node;
	}

	/* No right-hand children.  Everything down and left is
	 smaller than us, so any 'next' node must be in the general
	 direction of our parent. Go up the tree; any time the
	 ancestor is a right-hand child of its parent, keep going
	 up. First time it's a left-hand child of its parent, said
	 parent is our 'next' node. */
	while ((parent = rb_parent(node)) && node == parent->rb_right)
		node = parent;

	return parent;
}

struct rb_node *rb_prev(const struct rb_node *node)
{
	struct rb_node *parent;

	if (rb_parent(node) == node)
		return NULL;

	/* If we have a left-hand child, go down and then right as far
	 as we can. */
	if (node->rb_left) {
		node = node->rb_left;
		while (node->rb_right)
			node = node->rb_right;
		return (struct rb_node *) node;
	}

	/* No left-hand children. Go up till we find an ancestor which
	 is a right-hand child of its parent */
	while ((parent = rb_parent(node)) && node == parent->rb_left)
		node = parent;

	return parent;
}

void rb_replace_node(struct rb_node *victim, struct rb_node *new,
		struct rb_root *root)
{
	struct rb_node *parent = rb_parent(victim);

	/* Set the surrounding nodes to point to the replacement */
	if (parent) {
		if (victim == parent->rb_left)
			parent->rb_left = new;
		else
			parent->rb_right = new;
	} else {
		root->rb_node = new;
	}
	if (victim->rb_left)
		rb_set_parent(victim->rb_left, new);
	if (victim->rb_right)
		rb_set_parent(victim->rb_right, new);

	/* Copy the pointers/colour from the victim to the replacement */
	*new = *victim;
}

/******** Test code below ********/
#include <stdio.h>
#include <stdlib.h>

struct mytype {
	struct rb_node my_node;
	int num;
};

struct mytype *my_search(struct rb_root *root, int num)
{
	struct rb_node *node = root->rb_node;

	while (node) {
		struct mytype *data = container_of(node, struct mytype,
				my_node);

		if (num < data->num)
			node = node->rb_left;
		else if (num > data->num)
			node = node->rb_right;
		else
			return data;
	}

	return NULL;
}

int my_insert(struct rb_root *root, struct mytype *data)
{
	struct rb_node **tmp = &(root->rb_node), *parent = NULL;

	/* Figure out where to put new node */
	while (*tmp) {
		struct mytype *this = container_of(*tmp, struct mytype,
				my_node);

		parent = *tmp;
		if (data->num < this->num)
			tmp = &((*tmp)->rb_left);
		else if (data->num > this->num)
			tmp = &((*tmp)->rb_right);
		else
			return -1;
	}

	/* Add new node and rebalance tree. */
	rb_link_node(&data->my_node, parent, tmp);
	rb_insert_color(&data->my_node, root);

	return 0;
}

void my_delete(struct rb_root *root, int num)
{
	struct mytype *data = my_search(root, num);
	if (!data) {
		fprintf(stderr, "Not found %d.\n", num);
		return;
	}

	rb_erase(&data->my_node, root);
	free(data);
}

void print_rbtree(struct rb_root *tree)
{
	struct rb_node *node;

	for (node = rb_first(tree); node; node = rb_next(node))
		printf("%d ", rb_entry(node, struct mytype, my_node)->num);

	printf("\n");
}

//int main(int argc, char *argv[])
//{
//	struct rb_root mytree = RB_ROOT;
//	int i, ret, num;
//	struct mytype *tmp;
//
//	if (argc < 2) {
//		fprintf(stderr, "Usage: %s num\n", argv[0]);
//		exit(-1);
//	}
//
//	num = atoi(argv[1]);
//
//	printf("Please enter %d integers:\n", num);
//	for (i = 0; i < num; i++) {
//		tmp = malloc(sizeof(struct mytype));
//		if (!tmp)
//			perror("Allocate dynamic memory");
//
//		scanf("%d", &tmp->num);
//
//		ret = my_insert(&mytree, tmp);
//		if (ret < 0) {
//			fprintf(stderr, "The %d already exists.\n", tmp->num);
//			free(tmp);
//		}
//	}
//
//	printf("\nthe first test\n");
//	print_rbtree(&mytree);
//
//	my_delete(&mytree, 21);
//
//	printf("\nthe second test\n");
//	print_rbtree(&mytree);
//
//	return 0;
//}
